Bonded Ceramic Substrate Packaging Without Solder or Insulating Coating
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Solution Overview
Problem
Existing semiconductor device manufacturing processes are hindered by the need for adhesive application and insulating coating steps, which complicate productivity and increase the risk of ceramic plate cracking due to solder layer absence.
Innovation Solution
A semiconductor device design where the ceramic plate is directly bonded to the base plate without a solder layer, using an adhesive that contacts the ceramic plate's outer peripheral end to both adhere and insulate the case, eliminating the need for a separate insulating coating and reducing the likelihood of ceramic plate cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive application step and insulating coating step are both performed separately, then insulation reliability is improved, but manufacturing complexity and production time increase
Solution Approach 1:
The patent merges the adhesive application function and insulating coating function into a single adhesive layer. The adhesive is applied to the outer peripheral end of the ceramic plate to both adhere the case and provide electrical insulation for the circuit pattern, eliminating the need for a separate insulating coating step while maintaining both bonding strength and insulation reliability.
Solution Approach 2:
The adhesive serves multiple functions simultaneously: it acts as both the bonding agent to attach the case to the ceramic plate and as the insulating coating to protect the circuit pattern. This multi-functional approach reduces the number of manufacturing steps while ensuring both mechanical attachment and electrical insulation requirements are met.
2Reliability
If adhesive application step and insulating coating step are both performed separately, then insulation reliability is improved, but production time increases
Solution Approach 1:
The patent combines two separate manufacturing steps (adhesive application and insulating coating application) into a single step by using the adhesive to perform both functions. This reduces the total number of processing steps, decreases production time, and improves productivity while maintaining the required insulation reliability through proper adhesive selection and application.
Solution Approach 2:
The patent extracts the insulating coating step from the manufacturing process by relying on the adhesive's inherent insulating properties. By removing this redundant step, the production process becomes more efficient without compromising the insulation performance, as the adhesive naturally provides both bonding and insulation functions.
3Strength
If solder layer is used to bond ceramic plate to base plate, then bonding strength is improved, but risk of ceramic plate cracking increases
Solution Approach 1:
The patent replaces the traditional solder layer with an adhesive bonding method that uses a flexible, compliant material. The adhesive acts as a shock-absorbing layer that can accommodate thermal expansion differences between the ceramic plate and base plate without causing stress concentration that would lead to cracking, thereby maintaining bonding strength while improving ceramic plate integrity.
Solution Approach 2:
The patent changes the bonding mechanism from rigid solder bonding to flexible adhesive bonding. This parameter change in the bonding material's mechanical properties allows for stress distribution and reduces the risk of ceramic plate cracking during thermal cycling and mechanical operation, while still achieving sufficient bonding strength through proper adhesive selection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances productivity by eliminating the insulating coating step, improves insulation reliability, and reduces the risk of ceramic plate cracking, allowing for smaller device sizes and high-temperature operation while maintaining performance.
Implementation Method 1
an adhesive to adhere a lower portion of the case to an outer peripheral portion of the ceramic plate
Implementation Method 2
the adhesive is in contact with an outer peripheral end of the ceramic plate to an outer peripheral end of the circuit pattern
Implementation Method 3
a sealant, such as a silicone gel and an epoxy-based resin, is injected into the case to secure insulation and prevent contamination
Implementation Method 4
an insulating substrate including a ceramic plate integrally bonded to an upper surface of the base plate... for heat dissipation
Data Source
AI summary
It is an object to provide technology allowing for improvement in productivity of a semiconductor device. A semiconductor device includes: a base plate; an insulating substrate including a ceramic plate integrally bonded to an upper surface of the base plate with no solder layer therebetween and a circuit pattern disposed on an upper surface of the ceramic plate; a semiconductor element mounted on an upper surface of the circuit pattern; a case surrounding the insulating substrate and the semiconductor element over the base plate; an adhesive to adhere a lower portion of the case to an outer peripheral portion of the ceramic plate; and a sealant to seal the interior of the case, wherein the adhesive is in contact with an outer peripheral end of the ceramic plate to an outer peripheral end of the circuit pattern.